observational

[ ob-zur-vey-shuh-nl ]

/ ˌɒb zɜrˈveɪ ʃə nl /

of, relating to, or founded on observation, especially founded on observation rather than experiment.

Origin of observational

First recorded in 1825–35; observation + -al¹

ob·ser·va·tion·al·ly, adverb non·ob·ser·va·tion·al, adjective pre·ob·ser·va·tion·al, adjective

When a scientific truth arises, it is so because of observational and experimental consensus.

The Curious Passions of Mr. Cosmos: Neil deGrasse Tyson On Space, Climate, and Why Curiosity Wins Every Time |Scott Bixby |June 8, 2014 |DAILY BEAST
Meanwhile, some of the observational studies don't even show any benefit from insurance.

Study: Giving People Government Health Insurance May Not Make them Any Healthier |Megan McArdle |May 1, 2013 |DAILY BEAST
In both stories, the detached, observational voice calmly belies the impossibility of ever keeping a job ‘strictly business.’

Great Weekend Reads |The Daily Beast |July 3, 2011 |DAILY BEAST
All the lurking about unnoticed has allowed her to sharpen her observational skills.

10 Smart YA Reads |Shannon Donnelly |September 16, 2010 |DAILY BEAST

Observational astronomy, meanwhile, was advancing to Descriptive and practical astronomy.

Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7 |Various
He was hardly a practical astronomer in the observational sense.

Kepler |Walter W. Bryant
Even so with truth in observational science: it is built up of trifles patiently gathered together.

The Life of the Spider |J. Henri Fabre
For the most part it has been an observational rather than an experimental study.

Mimicry in Butterflies |Reginald Crundall Punnett
This first and oldest branch is known as "observational," or "practical astronomy."

A Popular History of Astronomy During the Nineteenth Century |Agnes M. (Agnes Mary) Clerke